It's apparently quite expensive here. Federal minimum wage is $7.25 an hour, while one reported cost [0] for the test is:
>$3,270 two weeks after his test. He will be responsible for $1,400 of that bill.
That's almost 10% of my annual gross before insurance and I have almost 14 years at my job. For someone working a minimum wage job that's more than 11 week's gross income. I imagine they are limiting the number of tests on people that could have any number of other things and waiting for symptoms to strongly point towards the virus due to the simple fact that the tests cost so much. If a patient can't pay, whatever hospital has to carry that cost for potentially years before the patient can repay them (or not get paid at all if it pushes someone to bankruptcy).
Until the government sets aside money to subsidize the tests, I imagine the testing rates will remain low.
[0] https://www.independent.co.uk/news/world/americas/coronaviru...